It is known in the prior art to mount a door on a hinge for controlling access to an enclosure by swinging the door open and closed and for providing means by which the hinge and door can be rectilinearly said into the enclosure. In such devices, the ends of a pivot upon which a door is mounted are disposed in respective linear slots, grooves, or channels in which the pivots are slid as the door is retracted or withdrawn as desired. The prior art means for mounting doors for swinging and sliding are deficient in at least two respects. Firstly, there is no positive engagement between the ends of the pivots on which the door is hinged to limit movement of one extremity of the door with respect to the other. Thus, as the door is slid in and out of the enclosure, depending upon the door's center of gravity, the point at which the pulling force or pushing force is applied, and the frictional forces between the pivots and the slot, groove or channel defining members, a moment is created causing the door to rotate in its plane thereby resulting in sagging and binding of the door.
An additional shortcoming of the prior art is that the frictional forces developed between the pivot and the slot or channel in which it is disposed require that substantial force be used to slide the door in and out of the enclosure. This causes wear of the pivot and channel forming members and often causes harsh or otherwise undesirable noise when the doors are slid in and out of the enclosure.